Threading device for motion picture film or the like

ABSTRACT

The housing of a motion picture projector defines a film path in which the film must advance toward the gate. The film is stored on a reel which is installed in a magazine and its leading end can be fully concealed in the interior of the magazine. The housing and the magazine accommodate portions of an automatic film threading device which causes the leading end of the film to enter the film path irrespective of the position of such leading end prior to threading. The threading device comprises a guide which is installed in the magazine to bear against the outermost convolution of convoluted film and can direct the leading end into the film path when the leading end is caused to assume a predetermined angular position with reference to the axis of the reel. A drive of the threading device can rotate the reel in a sense to pay out the film and to move the leading end to predetermined position in response to operation of the film transporting mechanism. This drive comprises an endless belt which is provided with external ribs adapted to engage and to entrain the leading end if the latter happens to be located between the belt and the guide when the threading operation is started. If the leading end is already located downstream of the belt, the reel is simply rotated until the leading end reaches the guide and is caused to enter the film path so as to move into the range of a driven member in the film transporting mechanism.

United States Patent Hans Heinen [72] Inventor Primary Examiner-LeonardD. Christian Munich, Germany Attorney-Michael S. Striker [21] Appl. No.754,566

22 F'led A 22 1968 I {45: Patented h n 26,3971 ABSTRAT: The housing of amotion picture projector [73] Assignee AGFA-Gevaert Altliengesellschafldefines a film path in which the film must advance toward theLevel-lumen, Germany gate. The film is stored on a reel which isinstalled in a [32] Priority Aug. 31, 1967 magazine and its leading endcan be fully concealed in the in- 33 Germany terior of the magazine. Thehousing and the magazine accom- [31] 1,547,068 modate portions of anautomatic film threading device which causes the leading end of the filmto enter the film path irrespective of the position of such leading endprior to threading. The threading device comprises a guide which isinstalled in the magazine to bear against the outermost convolution of[54] E FOR MOTION PICTURE convoluted film and can direct the leading endinto the film 12 Claim 1 Drawin Fig path when the leading end is causedto assume a predeterl g mined angular position with reference to theaxis of the reel. A [52] US. Cl 242/192, drive of the threading devicecan rotate the reel in a sense to 157 pay out the film and to move theleading end to predetermined [51] Int. Cl G03!) 1/04, ition in responseto operation of the film transporting G1 15/32 mechanism. This drivecomprises an endless belt which is pro- [50] Field of Search 242/198-vided with external ribs adapted to engage and to entrain the 352/7278,157, 158 leading end if the latter happens to be located between thebelt and the guide when the threading operation is started. If [56]References cued the leading end is already located downstream of thebelt, the UNITED STATES PATENTS reel is simply rotated until the leadingend reaches the guide 3,386,675 6/1968 Thomsen 242/198 and is caused toenter the film path so as to move into the 3,429,5 l 8 2/1969 McKee 242/192 range of a driven member in the film transporting mechanism.

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HANS HEINEN 'IHREADING DEVICE FOR MOTION PICTURE FILM OR THE LIKEBACKGROUND OF THE INVENTION The present invention relates tocinematographic apparatus, particularly to motion picture projectors,and more particularly to an improved threading device which can threadthe leading end of a motion picture film in a projector so that theleading end can be engaged by the film transporting mechanism.

Motion picture film is often stored in a magazine or cassette which canbe coupled to or inserted into the housing of a motion pictureprojector. As a rule, the leading end of the film must extend from themagazine in order to facilitate threading of film past the sprocket orsprockets of the film transporting mechanism, through one or more loopformers, through the projection gate, and on to the takeup spool. Thus,when the film is being rewound onto the spool in the magazine uponcompletion of projection of images on its frames, the operator must makesure that the leading end of the film (i.e., that end which is thetrailing end during rewinding) should not be permitted to enter theinterior of the magazine. This is achieved by providing the leading endof the with a bead or the like which is wide enough to prevent itspassage through the mouth of the magazine, or the rewinding operation ismonitored and the film arrested before its leading end can enter themagazine. In each instance, the film is subjected to excessive tensionalstresses, either because the reinforced leading end engages the surfacessurrounding the mouth or because the film must be brought to a suddenstop when the leading end approaches the mouth. This is undesirable,particularly because the rewinding operation is normally carried out ata high speed.

SUMMARY OF THE INVENTION An object of my invention is to provide acinematographic apparatus for projection of imageson frames of motionpicture film, which may but need not be stored in a magazine, and toprovide the apparatus with means for automatically threading the leadingend of the film into a predetermined film path irrespective of theangular position of such leading end prior to start of the threadingoperation.

Another object of the invention is to provide a cinematographicapparatus which can employ motion picture film stored in a magazine andwhich is equipped with a threading device capable of properlyintroducing the leading end of film into the film path regardless ofwhether or not the leading end of the film is concealed in the interiorof the magazine.

A further object of the invention is to provide the threading devicewith a novel drive for convoluted motion picture film and to constructand assemble the drive in such a way that it can move the leading end ofconvoluted film to an optimum position for introduction into the filmpath in response to operation of the film transporting mechanism of theapparatus.

An additional object of the invention is to provide a relatively simpleand inexpensive film threading device which occupies little room inand/or on the housing of a cinematographic apparatus, which comprises asmall number of simple parts, which need not be provided with a separateprime mover, and which can be concealed in the interior of the housingwhen the apparatus is not in use.

A concomitant object of the invention is to provide a threading devicewhich is not likely to damage or deface the film during threading andwhich is capable of introducing the leading end of convoluted film intothe film path within a very short interval of time.

The invention is embodied in a combination which includes acinematographic apparatus, particularly a motion picture projector,having a housing, a rotary reel carried by the hous ing and containing asupply of convoluted film having a leading end, confining means providedin or on the housing and defining a film path for conveying the filmlengthwise in response to unwinding of film from the reel, the confiningmeans having an inlet and one end of the film path, and a novelthreading device for introducing the leading end of convoluted film intothe inlet. The threading device comprises a drive for rotating the reelin a direction to unwind the film and to thereby place the leading endinto a predetermined angular position with reference to the axis of thereel, and guide means for directing the leading end into the inlet inresponse to further rotation of the reel in such direction.

The drive preferably comprises an endless elastic belt which can derivemotion from the film transporting mechanism of the apparatus and can bemade to bear against the outermost convolution of the supply on thereel. The belt may be provide with projections which can catch theleading end of the film and cause it to move to the aforementionedpredetermined angular position even if such leading end happens to belocated at the wrong side of the guide means when the threadingoperation begins.

The reel may but need not be accommodated in a magazine; if a magazineis used, the housing of the cinematographic apparatus is formed with awindow which registers with a window in the casing of the magazine whenthe latter is properly mounted on or in the housing, and the belt can bemade to extend through such windows and into engagement with theoutermost convolution of the supply of film in the magazine.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved film threading device itself, however, both as to itsconstruction and its mode of operation, together with additionalfeatures and advantages thereof, will be best understood upon perusal ofthe following detailed description of a specific embodiment withreference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single FIG. is a vertical sectionalview of a novel magazine for motion picture film and a fragmentaryvertical sectional view of a motion picture projector which embodies theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawing illustrates amotion picture projector which comprises a housing I having on one ofits walls mounting means for releasably supporting a magazine orcassette 2 for a reel 7 carrying a supply 6 of convoluted motion picturefilm 5. The leading end of the film 5 is shown at 5A. The mounting meansfor the magazine 2 comprises a ledge 1a on the housing 1 and a shiftablelocking member 3 which can engage an upturned rib 2d of the magazine. Asecond rib 2e is received in a groove defined by the ledge la. The meansfor moving the locking member 3 is not shown in the drawing.

The housing 1 accommodates a film transporting device which includes adriven sprocket wheel 4 extending into a eutout provided in a confiningchannel including wall members IA, 18 of the housing 1. These wallmembers define an elongated path ID in which the leading end 5A of thefilm 5 must advance in order to reach the teeth of the sprocket 4. Oncethe leading end 5A is engaged by such teeth, the film 5 is transportedin the customary way through a projection gate so that the images of itsframes are projected onto a screen. The leading end 5A can beautomatically coupled to a takeup reel or spool which collects the filmat the rate at which such film is being paid out by the reel 7 in themagazine 2. The direction in which the reel 7 must be rotated to pay outthe film 5 is indicated by arrow B. The aforementioned confining channelincluding the wall members 1A, 18 has inlet located at one end of thepath 1D and flanked by convex surfaces lb, 10. The casing of themagazine 2 has a mouth or outlet which is flanked by convex surfaces 2a,2b. This mouth is in registry with the inlet between the surfaces 1b, 10so that, one once the leading end SA assumes a predetermined angularposition with reference to the axis of the reel 7, and when the reel isrotated in a sense to pay out the film 5, the leading end A is'caused toautomatically slide along a guide 9 and to pass through the mouth of themagazine, through the inlet of the confining channel, and to advancelengthwise in the path 1D to move into the range of teeth on thesprocket 4. The guide 9 resembles a pawl which is pivotally secured tothe casing of the magazine 2, as at 9a, and is biased against theoutermost convolution of the supply 6 by a helical spring 8. This guideforms one component of a novel threading device which insures that theleading end SA of the film 5 finds its way into the path 1D and into therange of teeth on the sprocket 4 regardless of the angular position ofthe leading end 5A when the latter is concealed in the interior of themagazine 2. In other words,'the

novel threading device renders it possible to automatically introducethe leading end 5A between the'surface surfaces lb, 1c and to move itlengthwise toward the sprocket 4 regardless of the angular position ofthe leading end in the chamber 2f defined by the magazine 2.Consequently, and when the film 5 is being rewound onto the reel 7, theoperator need not pay any attention and need not monitor the travellingfilm because it is immaterial in what angular position of the leadingend 5A the film comes to a halt when the rewinding operation iscompleted. Also, the leading end 5A need not project from the mouth ofthe magazine when the latter is detached from the housing 1.

The aforementioned threading device further comprises a novel drivewhich preferably derives motion from the sprocket wheel 4 and can rotatethe reel 7 in the direction indicated by arrow B by way of the outermostconvolution of the supply 6.

tion and it its sprocket 4 advances the film 5 lengthwise in a sense todraw the film 5 off the reel7, the sprocket 4 rotates in the directionindicated by arrow A. The drive for the supply "6 comprises an endlessbelt or band 19 which is trained over pulleys or sheaves 17, 18 mountedon shafts l5, 16. The shaft is mounted on an arm ll which is pivotableon the shaft 12 of the sprocket 4, and the shaft 16 is mounted at theleft-hand end of a support or link 14 which is pivotable on the shaft 15and carries a shaft 14a for the lowerend of a second link 10. The latterhas an upper end which is mounted for pivotal movement on a pin 13carried by the lower wall member 113. Thebelt 19 has transverselyextending projections 19a in the form of ribs. The shaft 15 furthercarries a third pulley 20 and the shaft 12 carries a fourth pulley 21.The latter drives the pulley 20, and hence the pulley l7, belt 19 andpulley 18, by way of a crossed endless belt or cord 22. The belt 22 ispreferably elastic and causes the pulley 18 to rotate in a :clockwisedirection (arrow C) when the sprocket 4 is caused to rotate in thedirection indicated by arrow The arm 11 has spring 24 and with one endof a motion transmitting rod 25. The other end of the spring 24 isconnected to a post23 in the housing 1. This spring biases the arm 11 ina clockwise direction and thereby causes the left hand end turn of thebelt 19 to engage the outermost convolution of the supply 6. It will benoted that the housing 1 is provide with a window 1d which registerswith a window 20 in the casing of the magazine 2 when the latter isproperly attached to the housingflhe rod 25 serves as a means for movingthe belt 19 away from engagement with the supply 6, for example, whenthe shaft 7a for the reel 7 is driven ina sense to collect the film 5 onthis reel, i.e., when the reel rotates in a counterclockwise direction.The rod 25 can also disengage the belt [9 from the supply 6 as soon asor shortly after the leading end 5A of the film reaches the sprocket 4.

The axes of the shafts l5, 16 are preferably located in a radial planewhich also includes the axis of the shaft 7a and the belt 19 preferablyconsists of rubber or other suitable elastomeric material to furtherreduce the likelihood of an extension 110 which is connected with oneend of a helical damage to the film 5. It is advisable to employ a drivewhich rotates the pulley 18 at the peripheral speed of the sprocket 4.

The operation is as follows:

When the user 'wislies'to project the images of successive film framesonto a screen, not shown, the leading end 5A of the film 5 must be movedinto the range of teeth on the sprocket 4 so that this sprocket canthereupon transport the film past the gate and in front of theprojection lamp. During projection, the shaft 7a and/or the reel 7 ispreferably braked by a conventional braking device to insure that thelength of film 5 which extends between the supply 6 and the sprocket 4remains under requisite'tension. The manner in which the 'film 5 istransported -by' a claw p'ulldown'or the like (mounted in the housing 1downstream of the'sprocket 4) is well known in the art and is into shownin the drawing. When the projection of images is completed, the shaft isconnected to the film transporting mechanism which is operated inreverse so as to rotate the reel 7 in a counterclockwise directionwhereby the supply 6 of film 5 is restored and the leading end 5A entersthe chamber 2f of the magazine 2 to assume an unpredictable angularposition with reference to the axis of the shaft 7a and hence withreference to the guide 9. However, and since the cinematographicapparatus is provided with the improved film threading device, the shaft70 need not be arrested until after the leading end 5A is fullyconcealed in the interior of the magazine 2. I

In order to thereupon thread theleading end 5A into the path 1D, theoperator proceeds as follows: The rod 25 is released so that the spring24 is free to contract and to move the left-hand end turn of the belt 19against the outermost convolution of the supply 6. The film transportingmechanism is then started so that the sprocket 4 begins to rotate in thedirection indicated by arrow A and causes the pulley 18 to rotate in thesame direction (arrow C), i.e., the belt 19 causes the supply 6'torotate in the direction indicated by arrow B. If the leading end 5A ofthe film 5 happens to overlie the upper side of the guide 9, it isautomatically advanced through the mouth (between the surfaces 2a, 2b ofthe magazine 2) and through the inlet (between the surfaces lb, 1c) ofthe path 1D. As the supply 6 continues to rotate in the directionindicated by arrow B, the leading end 5A advances into the range ofteeth on the sprocket 4 and is thereupon transported lengthwise in thecustomary way.

However, if the leadingendSA happens to assume a position 5a which isindicated by broken lines, one of the ribs 19a on the travelling belt 19engages the tip of the leading end and causes the foremost part of thefilm 5 to flex, as shown at 5b by broken lines, until the leading end(moving in the direction indicatedby arrow C) enters the nip between thebelt 19 and the outermost convolution of the supply 6. The lattercontinues to rotate in the direction indicated by arrow B andautomatically moves the leading end to a predetermined optimum angularposition for transport into the path lD, i.e., to the aforementio'nedposition in which the leading end overlies the'upper side of the guide9. The transport of the leading end 5A enter into the path 1D and intothe range of teeth on the sprocket 4 is then effected in the previouslydescribed manner. If the peripheral speed of the sprocket 4 correspondsto the speed of the belt 19, the belt 19 does not slipwith reference tothe outermost convolution 'of the supply 6 even after the leading end 5Ais engaged by the teeth 'of the sprocket 4 and is advanced along thepath 1D toward the projection gate. This prevents damage to(particularly scratching of) convoluted film 5 on the reel 7 even if thebelt 19 in is'not disengaged from the supply 6a immediately after theleading end 5A reaches the sprocket 4.

The belt 19 is thereupon disengaged from the supply 6 by way of the rod25 which is moved to the right, as viewed in the drawing, so as to pivotthe arm 11 in a counterclockwise direction. The rod 25 may be actuatedautomatically, for example, by a customary loop former 'in the housingI. Alternatively, the rod 25 canbe actuated manually by way of a lever,knob, handle or analogous actuating means, not shown.

I claim:

1. In a cinematographic apparatus, particularly in a motion pictureprojector, a combination comprising a housing; a rotary reel carried bysaid housing and containing a supply of convoluted film having a leadingend; confining means providedin said housing and defining a path whereinthe film is conveyed lengthwise in response to unwinding of said supplyfrom said reel, said confining means having an inlet at one end of saidpath; and threading means for introduction the leading end of said filminto said inlet, comprising a drive for rotating .said reel by way ofsaid supply of convoluted film in a direction to unwind the film and tothereby place said leading into into a predeterminedangular positionwith reference to the axis of said reel, said drive comprising anelement operative to engage the outermost convolution of said supply andto thereby rotate the reel in said direction.

2. A combination as defined in claim 1, wherein said element of saiddrive is an endless flexible element element.

3. A combination as defined in claim 2, wherein said flexible elementconsists of elastomeric material.

4. A combination as defined in claim 2, wherein sad said drive meansfurther comprises at least one rotary member, said flexible elementbeing trained over said rotary member in the region where it engagessaid supply.

5. A combination as defined in claim 2, wherein said drive means furthercomprises a pair of pulleys having axes located in a common plane withthe axis of said reel, a said flexible element being trained over saidpulleys.

6. A combination as defined in claim 5, further comprising a support forsaid pulleys, said support being movable between first and secondpositions in which said flexible element respectively engages with andis disengaged from said supply.

7. A combination as defined in claim 6, further comprising a magazineaccommodating said supply and said reel, a said housing having a firstwindow and said magazine having a second window registering with saidfirst window, said flexible element extending through said windows andinto engagement with the supply of film in said magazine in the firstposition of said support.

8. A combination as defined in claim 7, further comprising mountingmeans detachably securing said magazine to said housing, said magazinehaving a mouth in registry with said inlet and said guide means beingprovide in the interior of said magazine.

9. A combination as defined in claim 6, wherein said support ispivotable about the axis of one of said pulleys.

10. A combination as defined in claim 6, further comprising means forbiasing the support to a said first position.

11. In a cinematographic apparatus, particularly in a motion pictureprojector, a combination comprising a housing; a rotary reel carried bysaid housing and containing a supply of convoluted l film having aleading end; confining means provided in said housing and defining apath wherein the film is conveyed lengthwise in response to unwinding ofsaid supply from said reel, said confining means having an inlet at oneend of said path; film transporting means including a rotary sprockethaving teeth extending into said path downstream of said inlet to engageand advance the leading end of said film when such leading end advancesbeyond said inlet; and threading means for introducing the leading endof said film into said inlet, comprising a drive for rotating said reelby way of said supply of convoluted film in a direction to unwind thefilm and to thereby place said leading end into a predetermined angularposition with reference to the axis of said reel, and guide means fordirecting said leading end into said inlet in response to furtherrotation of the reel in said direction, said drive comprising an endlessflexible element operative to engage the outermost convolution of saidsupply an to thereby rotate the reel in said direction, and meansderiving motion from said film transporting means and arranged to movesaid flexible element at the peripheral speed of said sprocket.

12. In a cinematographic apparatus, particularly in a motion pictureprojector, a combination comprising a housing having a window; a rotaryreel carried by said housing and containing a supply of convolutedfilmhaving a leading end and being outwar ly adjacent to said window;confining means provide in said housing and defining a path forconveying the film lengthwise in response to unwinding of said supplyfrom said reel, said confining means having an inlet at one end of saidpath; and threading means for introducing the leading end of said filminto said inlet, comprising a drive for rotating said reel by way ofsaid supply of convoluted film in a direction to unwind the film and tothereby place said leading end into a predetermined angular positionwith reference to the axis of said reel, and guide ineans for directingsaid leading end into said inlet in response to further rotation of thereel in said direction, said drive comprising a support provided in saidhousing, a pair of pulleys rotatably mounted on said support and havingaxes located in a common plane with the axis of said reel, and anendless flexible film-engaging element trained over said pulleys andarranged to by driven in a direction to unwind the film from said reelwhen such element engages the outermost convolution of said supply, saidsupport being movable substantially radially of said reel to and from anoperative position in which the support extends through said window andone of said pulleys maintains the flexible element in engagement withthe outermost convolution of said supply.

1. In a cinematographic apparatus, particularly in a motion pictureprojector, a combination comprising a housing; a rotary reel carried bysaid housing and containing a supply of convoluted film having a leadingend; confining means provided in said housing and defining a pathwherein the film is conveyed lengthwise in response to unwinding of saidsupply from said reel, said confining means having an inlet at one endof said path; and threading means for introduction the leading end ofsaid film into said inlet, comprising a drive for rotating said reel byway of said supply of convoluted film in a direction to unwind the filmand to thereby place said leading into into a predetermined angularposition with reference to the axis of said reel, said drive comprisingan element operative to engage the outermost convolution of said supplyand to thereby rotate the reel in said direction.
 2. A combination asdefined in claim 1, wherein said element of said drive is an endlessflexible element element.
 3. A combination as defined in claim 2,wherein said flexible element consists of elastomeric material.
 4. Acombination as defined in claim 2, wherein sad said drive means furthercomprises at least one rotary mEmber, said flexible element beingtrained over said rotary member in the region where it engages saidsupply.
 5. A combination as defined in claim 2, wherein said drive meansfurther comprises a pair of pulleys having axes located in a commonplane with the axis of said reel, a said flexible element being trainedover said pulleys.
 6. A combination as defined in claim 5, furthercomprising a support for said pulleys, said support being movablebetween first and second positions in which said flexible elementrespectively engages with and is disengaged from said supply.
 7. Acombination as defined in claim 6, further comprising a magazineaccommodating said supply and said reel, a said housing having a firstwindow and said magazine having a second window registering with saidfirst window, said flexible element extending through said windows andinto engagement with the supply of film in said magazine in the firstposition of said support.
 8. A combination as defined in claim 7,further comprising mounting means detachably securing said magazine tosaid housing, said magazine having a mouth in registry with said inletand said guide means being provide in the interior of said magazine. 9.A combination as defined in claim 6, wherein said support is pivotableabout the axis of one of said pulleys.
 10. A combination as defined inclaim 6, further comprising means for biasing the support to a saidfirst position.
 11. In a cinematographic apparatus, particularly in amotion picture projector, a combination comprising a housing; a rotaryreel carried by said housing and containing a supply of convoluted lfilm having a leading end; confining means provided in said housing anddefining a path wherein the film is conveyed lengthwise in response tounwinding of said supply from said reel, said confining means having aninlet at one end of said path; film transporting means including arotary sprocket having teeth extending into said path downstream of saidinlet to engage and advance the leading end of said film when suchleading end advances beyond said inlet; and threading means forintroducing the leading end of said film into said inlet, comprising adrive for rotating said reel by way of said supply of convoluted film ina direction to unwind the film and to thereby place said leading endinto a predetermined angular position with reference to the axis of saidreel, and guide means for directing said leading end into said inlet inresponse to further rotation of the reel in said direction, said drivecomprising an endless flexible element operative to engage the outermostconvolution of said supply an to thereby rotate the reel in saiddirection, and means deriving motion from said film transporting meansand arranged to move said flexible element at the peripheral speed ofsaid sprocket.
 12. In a cinematographic apparatus, particularly in amotion picture projector, a combination comprising a housing having awindow; a rotary reel carried by said housing and containing a supply ofconvoluted film having a leading end and being outwardly adjacent tosaid window; confining means provided in said housing and defining apath for conveying the film lengthwise in response to unwinding of saidsupply from said reel, said confining means having an inlet at one endof said path; and threading means for introducing the leading end ofsaid film into said inlet, comprising a drive for rotating said reel byway of said supply of convoluted film in a direction to unwind the filmand to thereby place said leading end into a predetermined angularposition with reference to the axis of said reel, and guide means fordirecting said leading end into said inlet in response to furtherrotation of the reel in said direction, said drive comprising a supportprovided in said housing, a pair of pulleys rotatably mounted on saidsupport and having axes located in a common plane with the axis of saidreel, and an endless flexible film-engaging element trainEd over saidpulleys and arranged to by driven in a direction to unwind the film fromsaid reel when such element engages the outermost convolution of saidsupply, said support being movable substantially radially of said reelto and from an operative position in which the support extends throughsaid window and one of said pulleys maintains the flexible element inengagement with the outermost convolution of said supply.